I just happened to get these two FieldRef's right (purely because they were easy to guess the names of) - but is there an actual list available anywhere for me to find out the names of the published date fields fieldrefs etc.

If you want to use a tool that exposes various properties of the SP object model (basically allows you explore all of the sites' fields, lists, content types, and other nitty gritty) and you don't want to have to return to sites like this to discover the next magical method, you really ought to try installing SharePoint Manager 2010